In a radio communication network, such as a so-called Long Term Evolution (LTE) network, there are one or more network nodes, so called radio base stations, arranged for controlling and scheduling data traffic to and from user equipment present within a geographical area or areas, denoted cell(s), served by the radio base station.
The radio base station consequently comprises, for each such cell, equipment in the form of one or more receivers and transmitters, or transceivers, employed for effecting the wireless data communication. These receivers and transmitters consume a significant amount of energy even when currently not transmitting or receiving any data. This energy required to keep the equipment on is denoted static energy consumption to distinguish it from the dynamic energy consumption relating to the energy needed for actually transmitting and receiving data over the air interface.
The main focus in terms of reducing energy consumption in the art has been directed towards decreasing the dynamic energy consumption, mainly by improving the efficiency of the power amplifiers in the receivers and transmitters of the radio base station. However, during a large portion of the operation time of the radio base stations, the traffic load and demands of the radio base stations are not that high, implying that the static energy consumption becomes a major part of the total energy consumption of the radio base stations.
WO2009/041871 discloses a technique for energy reduction in an LTE network. This technique involves performing measurements of system load in a cell. Based on these measurements, a decision is made to vary the number of available downlink sub frames, which are used by a radio base station for the transmission of data to user equipment in the cell. This will reduce the dynamic energy consumption as some of the sub frames will be declared idle and the transmitters can consequently be in stand-by mode during these idle sub frames.